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J Speth

Publications and source records attributed to J Speth.

36 records · Page 2Linked to original sources
PubMed1989

Pharmacokinetics of benzathine penicillin G: serum levels during the 28 days after intramuscular injection of 1,200,000 units.

Because of published data suggesting the inadequacy of once-every-4-weeks intramuscular injections of benzathine penicillin G for secondary rheumatic fever prevention, serum penicillin levels were determined at 1, 3, 10, 21, and 28 days after administration of 1,200,000 units of this repository penicillin. A total of 193 samples were studied. Mean serum penicillin levels remained greater than or equal to 0.02 micrograms/ml for 21 days, but by 28 days only 44% of the serum samples had detectable levels of penicillin and only 36% had levels greater than or equal to 0.02 micrograms/ml. Patients weighing more than 45 kg had significantly lower serum penicillin levels than did those who weighed less. There were similar correlations with body surface area and with age. These data indicate that a significant percentage of patients receiving benzathine penicillin G prophylaxis for prevention of recurrent attacks of rheumatic fever are not protected during the fourth week. More frequent administration of benzathine penicillin G should be considered in instances of high risk of recurrence of rheumatic fever.

Adolescent↗
PubMed1988

Clearance of a novel recombinant tissue plasminogen activator in rabbits.

The pharmacokinetic properties of hPA(B), characterized by the insertion of a urokinase kringle coding region before the double kringle of tPA plus the complete tPA coding region, were investigated and compared to those of melanoma tPA (mtPA). Mean peak plasma concentrations at the end of infusion were 4.7 micrograms/ml for hPA(B) and 4.6 micrograms/ml for mtPA. The pharmacokinetics of both hPA(B) and mtPA showed a biexponential disappearance from plasma which is consistent with a two-compartment model of t 1/2 (lambda 1) = 2 minutes, t 1/2 (lambda 2) = 58 minutes for hPA(B), and t 1/2 (lambda 1) = 2.2 minutes, t 1/2 (lambda 2) = 61 minutes for mtPA. However, this very fast decaying lambda 1 phase of mtPA lasted five times longer than that of hPA(B) which resulted in very low concentrations of mtPA. Thus, hPA(B) exhibited larger AUC, slower clearance rate, and smaller volume of distribution (P less than 0.01) than those of mtPA. The fibrinolytic activity of hPA(B) in rabbit plasma as determined by zymography lasted up to 120 minutes after the end of infusion as compared to that of 2 minutes for mtPA. This indicates that mtPA, despite its t 1/2 (lambda 2) being similar to that of hPA(B), is no longer at physiologically meaningful concentrations at the start of the lambda 2 phase.

Animals↗